@db1979 

FYI:

MBps = Megabyte per second

Mbps = Megabit per second

8 Bits = 1 Byte

Usually, when talking about data transmission rates, we will refer to Mbps. This is the most common and is much more precise for comparing devices. You may, however, often see data plans from ISPs advertised as being in Bytes. So while a gigabit plan is 1000Mbps, a GigaBYTE plan is really 1000MBps * 8 for ~8000mbps. Which ends up being quite the difference when it comes to actual data transfer

The AV500 Refers to the Technical Specification that it follows, for powerline connections, this is important if you were to add other nodes to your home, as the rate between devices is limited to what the slowest node on the network can achieve. This means that if you were to add a AV1200 class of powerline as the main, any other powerline unit will be limited to the 500mbps that the PA4010 is capable of seeing on the electrical wires, rather than the ethernet speeds. This is also important because Powerline is subject to such degradation that the whole speed would not be seen on the satellite nodes. 

Basically, Powerline Speeds that are for electrical wiring are standardized to allow room for expansion; if the device was only capable of seeing 100mbps then all the powerline nodes attached to the network would also only be able to see 100mbps, even if it supports much more.